Biology Chapter 10: Homeostasis

Question 1

Excretory system

Answer 1

serves many functions, including the regulation of blood pressure, blood osmolarity, acid-base balance

Question 2

kidney

Answer 2

produces urine, which dumps into the ureter at the renal pelvis.

Question 3

Bladder

Answer 3

collects urine until it is excreted through the urethra

Question 4

Kidney contains

Answer 4

a cortex and a medulla - each kidney has a hilum which contains a renal artery, renal vein and ureter.

Question 5

Portal system

Answer 5

a circuit of blood in which there are two capillary beds in tandem connected by an artery or vein; examples include the hypophyseal, hepatic and renal portal system.

Question 6

Blood from the renal artery flows into..

Answer 6

the afferent arterioles, which form glomeruli in Bowman’s capsule (the first capillary bed).

Question 7

Blood flows from Bowman’s capsule into..

Answer 7

the efferent arteriole to the vasa recta, which surround the nephron (the second capillary bed), before leaving the kidney through the renal vein.

Question 8

Detrusor muscle

Answer 8

muscular lining of the bladder. It is under parasympathetic control.

Question 9

Internal urethral sphincter

Answer 9

consists of smooth muscle and is under involuntary (parasympathetic) control.

Question 10

external urethral sphincter

Answer 10

consists of skeletal muscle and is under voluntary control

Question 11

Kidney participates in solute movement through three processes:

Answer 11

• Filtration
• Secretion
• Reabsorption

Question 12

Filtration

Answer 12

movement of solutes from blood to filtrate at Bowman’s capsule. The direction and rate of filtration is determined by Starling forces, which account for the hydrostatic and oncotic pressure differentials between the glomerulus and Bowman’s space

Question 13

Secretion

Answer 13

the movement of solutes from blood to filtrate anywhere other than Bowman’s capsule

Question 14

Reabsorption

Answer 14

the movement of solutes from filtrate to blood

Question 15

Proximal convoluted tubule

Answer 15

site of bulk reabsorption of glucose, amino acids, soluble vitamins, salt and water. It is also the site of secretion for hydrogen ions, potassium ions, ammonia and urea

Question 16

descending limb of the loop of Henle

Answer 16

permeable to water, but not sale; therefore as the filtrate moves into the more osmotically conventrated renal medulla, water is reabsorbed from the filtrate.

Question 17

Countercurrent multiplier

Answer 17

created by the vasa recta and the nephron flowing in opposite directions - allows for maximal reabsorption.

Question 18

Acsending limb of the loop of Henle

Answer 18

permeale to salt, but not to water; therefore, salt is reabsorbed both passively and actively.. The diluting segment is in the outer medulla; because salt is actively reabsorbed in this site, the filtrate actually becomes hypotonic compared to the blood.

Question 19

collecting duct

Answer 19

responsive to both aldosterone and antidiuretic hormone and has variable permeability, which allows reabsorption of the right amount of water depending on the body’s needs.

Question 20

When blood pressure and volume are low, what hormonal systems are activated?

Answer 20

aldosterone, antidiuretic hormone

Question 21

Aldosterone

Answer 21

steroid homone
regulated by the renin-angiotensis-aldosterone system that increases sodium reabsorption in the DCT and collecting duct, increasing water reabsorption.
Results in increased volume but not change in osmolarity

Question 22

Antidiuretic hormone

Answer 22

peptide hormone synthesized by the hypothalamus and released by the posterior pituitary. Its release is stimulated not only by low blood volume, but also by high blood osmolarity.
Increases permeability of the collecting duct to water, increasing water reabsorption.
Results in increased blood volume and a decreased blood osmolarity.

Question 23

How can the kidney regulate pH?

Answer 23

Selective reabsorption or secretion of bicarbonate or H+

Question 24

What are the three layers of the skin?

Answer 24

hypodermis, dermis and epidermis

Question 25

What are the five layers of the epidermis?

Answer 25

stratum basale
stratum spinosum 
stratum granulosum 
stratum lucidum
stratum corneum

Question 26

What is the stratus basale made of?

Answer 26

stem cells that proliferate to form keratinocytes.

Question 27

Where are keratinocyte nuclei lost?

Answer 27

the stratum granulosum

Question 28

What forms in the are in the stratum corneum?

Answer 28

many thin layers.

Question 29

Melanocytes

Answer 29

produce melanin, which protects the skin from DNA damage caused by ultraviolet radiation; melanin is passed to keratinocytes.

Question 30

Langerhans cells

Answer 30

special macrophages that serve as antigen resenting cells in the skin.

Question 31

What are the two layers of the dermis?

Answer 31

papillary and reticular

Question 32

Merkel cells

Answer 32

sensory - deep pressure and texture

Question 33

Free nerve endings

Answer 33

sense pain

Question 34

Meissner’s corpuscles

Answer 34

sense light touch

Question 35

Ruffini endings

Answer 35

sense stretch.

Question 36

Pacinian corpuscles

Answer 36

sense deep pressure and vibration

Question 37

The hypodermis contains

Answer 37

fat and connective tissue and connects the skin to the rest of the body.

Question 38

Cooling mechanisms of the skin

Answer 38

sweating, which absorbs heat from the body through evaporation of water from sweat and vasodilation. Sweat glands are innervated by postganglionic cholinergic sympathetic neurons

Question 39

Warming mechanisms

Answer 39

Include piloerection, in which arrector pili muscles contract causing hairs to stand on end, vasoconstriction, shivering, and insulation provided by fat.